Tertiary amyl phenol sulfides have been widely used as sulfur donors in the vulcanization of sulfur curable rubber for many years. Millions of pounds of this material have been supplied to the rubber industry in fiber or steel drums. As presently known in the industry, this material is sold in the form of a solid tacky chunk. When the rubber formulator wants to use this large chunk of tacky material in compounding rubber, he has a choice of either chopping up the fiber board drum with an axe or else of heating the metal drum of tertiary amyl phenol sulfides in a heated bath and pouring off the melted sulfides as needed. Either method of handling the sulfides is expensive, time consuming, wasteful and leaves the work area in a dirty condition.
When a fiber drum of tertiary amyl phenol sulfide is chopped with an axe, the sulfide will scatter over the work area, and since it is quite tacky, it will adhere to the floor as well as to the workers shoes. As the residue builds up on the floor a dirty and dangerous condition in the work area is created. When tertiary amyl phenol sulfides are shipped in metal drums (approximately 325 pounds net weight) the tacky glob must be heated to melt the sulfides to the liquid form before they can be used in small quantities in compounding the rubber. Extended heating and holding the sulfide in the molten state causes thermal degradation of the product and discoloration.
The tacky nature of the tertiary amyl phenol sulfides as used in the rubber industry up to the time of my invention was recognized in U.S. Pat. No. 2,422,156 wherein a mole ratio of two moles of tertiary amyl phenol to one mole of sulfur monochloride is disclosed. This patent also discloses the use of tertiary amyl phenol sulfides as a vulcanization agent (sulfur donor) for rubber and the disclosure of this patent is incorporated herein by reference.
Commercial products of para tertiary amyl phenol sulfides and polysulfides have been supplied to the rubber industry up to the present time in which the mole ratio of para tertiary amyl phenol to sulfur monochloride has ranged from 2 to 1 to 1 to 1. All of these products have been quite tacky and difficult to remove from the shipping containers.
Various additives have been incorporated in para tertiary amyl phenol sulfides when they are used as vulcanization agents. Industrial White oil in small quantities has been used in commercial products. Large amounts of stearic acid (up to 35% by weight) and oleic acid (45% by weight) have also been used but with little success. Adding up to 25% by weight of a diatomaceous earth has provided a free flowing granular product but it is an expensive diluent and is also a contaminant in the rubber when it is vulcanized.